The present invention is directed generally to air filters, and more particularly to an improved in-line air filter apparatus for providing filtered air having reduced turbulence to the engine air intake hose of an internal combustion engine and thereby reducing the pressure drop across the air filter apparatus.
In the prior art, the presently available air filter devices for use on internal combustion engines (for example, as used in motor vehicles) have had at least two substantial deficiencies: (1) high noise levels generated by the flow of air, and (2) high pressure drop across the entire air filter device. Both these characteristics have been found to be attributable to highly turbulent air flow conditions caused by air flow directional changes and abrupt internal wall configuration changes within the air filter device.
Intake air noise reduction is a substantial concern to automotive engineers because any additional air noise present adds a further component of noise to the noise level already emanating from the hood of the automobile from other elements of the engine, and is thus audibly further detectable by the occupants of the passenger compartment. Pressure drop across the air filter intake system is also a primary concern of automotive engineers, due to the inversely proportional relationship between the air flow restriction and the efficiency of the engine. As the air flow restriction increases in the air induction system, the horsepower and fuel economy of the engine are commensurately decreased.
Accordingly, it is a principal object of the improved in-line air filter apparatus of the present invention to alleviate materially these difficulties, defects, deficiencies of the prior art. In further particular, it is also a material object of the improved in-line air filter apparatus of the present invention to provide novel structure for supplying filtered air to the engine air intake hose of an internal combustion engine, in which novel structure the air stream during filtration is of reduced turbulence and which results in reduced pressure drop across the air filter apparatus.